The following documents may be considered related art:    Patent Application PCT/DE2004/001646, Freitag, L; Method and arrangement for respiratory support for a patient airway prosthesis and catheter    U.S. Patent Application 20050005936, Wondka; Methods, systems and devices for improving ventilation in a lung area    U.S. Pat. No. 5,419,314, Christopher; Method and apparatus for weaning ventilator-dependent patients    U.S. Patent Application 20050247308, Frye, Mark R.; High efficiency liquid oxygen system    U.S. Pat. No. 4,938,212, Snook; Inspiration oxygen saver    Transtracheal Open Ventilation in Acute Respiratory Failure Secondary to Severe Chronic Obstructive Pulmonary Disease Exacerbation American Journal of Respiratory and Critical Care Medicine Vol 173. pp. 877-881, (2006), Cesare Gregoretti    Preliminary observations of transtracheal augmented ventilation for chronic severe respiratory disease. Respir Care. 2001 January; 46(1):15-25, Christopher K L    Reduced inspiratory muscle endurance following successful weaning from prolonged mechanical ventilation. Chest. 2005 August; 128(2):553-9 Chest. 2005 August; 128(2):481-3. Chang A T    A comparison in a lung model of low- and high-flow regulators for transtracheal jet ventilation. Anesthesiology. 1992 July; 77(1):189-99. Gaughan S D, Benumof J L    Tracheal perforation. A complication associated with transtracheal oxygen therapy. Menon A S—Chest—1 Aug. 1993; 104(2): 636-7    Dangerous complication of transtracheal oxygen therapy with the SCOOP® system. Rothe T B—Pneumologie—1 Oct. 1996; 50(10): 700-2
Patients suffering from respiratory impairment are under-oxygenated due to deteriorating lung structure and are fatigued due to the strenuous work required to get air in and out of their compromised lungs. This work leads to patients becoming dormant to reduce their oxygen consumption to reduce their work of breathing (WOB) and in turn this dormancy leads to other health problems. Long term oxygen therapy (LTOT) is a gold standard therapy widely used for decades to assist patients suffering from respiratory impairment. Typically patients are provided 1-6 LPM of continuous oxygen flow into the nose via an oxygen nasal cannula. The supplemental oxygen increases the concentration of oxygen in the lung and alveolii therefore increasing the oxygen delivered to the body thus compensating for the patient's poor lung function. Improvements to LTOT have been more recently introduced such as transtracheal oxygen therapy (TTOT) and demand oxygen delivery (DOD). TTOT (U.S. Pat. No. 5,419,314) is a potential improvement over LTOT in that the oxygen is delivered directly to the trachea thus closer to the lung and thus the oxygen is not wasted in the upper airway and nasal cavity. DOD systems (U.S. Pat. No. 4,938,212) have been devised to sense when the patient is inspiring and deliver oxygen only during inspiration in order to conserve the source of oxygen, a concern in the home care or ambulatory setting although not a concern in the hospital setting where the oxygen source is plentiful. LTOT, TTOT and DOD are useful in improving diffusion of oxygen into the tissues by increasing the oxygen level in the lung and bloodstream, but these therapies all have the drawback of not providing any real ventilatory support for the patient and the excessive WOB is not relieved, especially during the types of simple exertion which occur during normal daily activities, like walking or climbing stairs.
Continuous Positive Airway Pressure (CPAP) ventilation has been used extensively to provide ventilatory support for patients when LTOT alone is insufficient to compensate for a patient's respiratory impairment. However, CPAP is non-portable and is obtrusive to patients because of the nasal mask that must be worn. Further, CPAP can inadvertently train the respiratory muscles to become lazy since the neuromuscular system gets acclimated to the artificial respiratory support, a syndrome known within the respiratory medical community.
Transtracheal High Frequency Jet Ventilation (TTHFJV) as described by Benumof has also been used, for example for emergency ventilation, typically using a small gauge catheter introduced into the trachea. Frequencies are typically 60 cycles per minute or greater, driving pressures are typically around 40 psi, and flow rates are typically greater than 10 LMP therefore requiring a blended oxygen air mixture and heated humidification. TTHFJV is not a portable therapy and is not appropriate as a ventilation assist therapy for an ambulatory, spontaneously breathing, alert, non-critical patient.
Transtracheal Open Ventilation (TOV) as described by Gregoretti has been used as an alternative to mechanical ventilation which uses an endotracheal tube. The purpose of TOV is to reduce the negative side effects of invasive ventilation such as ventilator associated pneumonia. Typically a 4 mm catheter is inserted into a tracheostomy tube already in the patient and the other end of the catheter is attached to a conventional mechanical ventilator which is set in assisted pressure control mode and mechanical breaths are delivered into the trachea synchronized with the patients breath rate. However because the ventilator delivers a predetermined mechanical breath set by the user the ventilator is breathing for the patient and is not truly assisting the patient. TOV is non-portable and is designed to provide a high level or complete support of a patients respiration.
Transtracheal Augmented Ventilation (TAV) as described by Christopher is a therapy in which high flow rates typically greater than 10 LPM of a humidified oxygen/air blend are delivered continuously into the trachea or can be delivered intermittently or synchronized with the patients' breathing pattern. TAV is a good therapy to provide ventilatory support for patients with severe respiratory insufficiency, however TAV is not suitable for an ambulatory portable therapy because of the high flow and humidification requirement.
Current oxygen delivery therapies or ventilation therapies are either too obtrusive, or are not sufficiently compact or mobile, or are limited in their efficacy and are therefore not useful for the vast population of patients with respiratory insufficiency that want to be ambulatory and active while receiving respiratory support. Specifically a therapy does not exist which both (1) oxygen delivery to increase oxygen diffusion into the blood stream, and (2) ventilation support to relieve the WOB in a mobile device. The invention disclosed herein provides unique and novel solutions to this problem by providing an unobtrusive, ultra compact and mobile, clinically effective system that provides both oxygen diffusion support and ventilation support to address respiratory insufficiency.